Dry galvanic cell



A. RUGLER .DRY GALVANIG CELL Filed Sept. 26, 1925 v /n vemfol':

Patented Dec. 7, 1926.

UNITED STATES 1,609,665, PATENT OFFICE.

ALFRED R'tl'G-LER, F BERLIN'-ERKNER, GERMANY, ASSIGNOR TO THE FIRM 0FELE-K TROTEGHNISCHE FABRIK SCHMIDT & (30., 0E BERLIN, GERMANY.

DRY GALVANIC CELL.

Application filed September 26, 1925, Serial No. 58,769, and in GermanyOctober 3, 1924.

The chemical process at work in a galvanic dry cell, when current isbeing generated, produces an increase in volume of the electrolyte,which has been thickened with meal, starch or the like, leading, forinstance, in the Ordinary sal-ammoniac electrolytes, to solid and liquidreaction products such as zinc salts, and water, on the onehand, and onthe other to gases, such as ammonia and hydrogen.

Ithappens then that if there is not suflicient room for the expandingelectrolyte, it escapes to the outside through the gas-dis chargeopenings or else springs the casting when it is a hermetically sealedcell or explodes the holder. If a free space is left above theelctrolyte for its expansion the electrolyte shows a tendency to spreadover the entire upper surface of the depolariza- 8.0 tion electrode,covering' the latter completely. This prevents more 'or less the escapeof gas for instance ammonia produced within the cell and causes thevoltage of the charged cell to quickly fall off so that its useful lifeis very appreciably diminished. a

The drawbacks just described are, according to the present invention,removed by a device which, on the one hand, shuts off the upper surfaceof the depolarization electrode to the electrolyte as it rises and onthe other hand, thereby facilitates a permanent .gas exchange-betweenthe electrode and the outer air. It consists of a hollowbody ofcylindrical or other shape, either open below orj suitably perforatedwhich is forced- (shrunk) or otherwise closely secured on the upper partof the depolarization material surrounding the carbon ole. This body canalso, in the making of t e depolarization electrodes, be fixedly securedto the latter. The electrolyte as it rises is now taken up by the,suitably sized space between the outer wall ofthis addedbody and thezinc vessel, while the inner space of the body which may be. subdividedif desired is.utiliz ed for the circulation of the gas.

\ The as exchan e (communication) hereby rendered possible with theexternal atmosphere, is still further promoted by the insertion of two,or in certain cases more,

ventilation pipes .of different lengths into the cover seal. The size ofthese is to be determined by arranging that the shorter ones terminatebelow the seal while others reach nearly to the free upper surface ofthe depolarization material. It has been found that such arrangement ofpipes of difierent len ths not only allows the escape of gases producedwithin the cell but causes at the same time a circulation of atmosphericair which increases the depolarizing effect of the depolarizationelectrode.

A constructional form of the cell is shown in the drawing.

Figure 1 representing a longitudinal section, through the cell andFigure 2 a cross section.

1 denotes the carbon rod surrounded in the usual way, by thedepolarization mate rial 2. The space between this depolarizaw tionelectrode and the zinc vessel 3 is filled up as usual with the thickenedelectrolyte 4. The body fitted thereon consists of two co-axialcylinders 5 and 6 ofany suitable insulating material, these beingattached to each other by stays or struts, after the manner of wheel,spokes. This body is forced (pressed) on to the depolarization materialbeing closed off from above by a disc 8 on which the seal 9 is fused.

' Ventilation .pipes are led through the latter and through the disc,the number of these being in this particular case limited to two. Thepipe 10 reaches to just under the closing disc 8 while the pi e 11terminates a little way above the epolariza- I tion material 2.

By the closing-off of the depolarization upper surface against theelectrolyte which is efiected by the arrangement just described and bythe employment at the same time of vigorous ventilation, a ,veryconsiderable rise is effected in the efliciency of the cell. .What Iclaim is 1. A primary dry galvanic cell comprising an outer-metallictubularelectrode and an inner compound electrode consisting of a carbonrod and a surrounding mass of depolarizing material'and a thickenedelectrolyte between said outer tubular metallic electrode and said massof depolarizing material, a gas chamber being provided above. said massof depolarizing material said chamber having a circumferential walladapted to prevent the electrolyte from overflowing the upper surface ofthe depolarizing material, so as to allow free escape of gas throughsubstantially the whole upper surface of the depolarizing ms, the cellmass of depolarizing material said chamber having a circumferential walladapted to prevent the electrolyte from entering into said chamber, thechamber being closed at the top, the closure having inserted thereinventilation tubes ending within the chamber at different distances fromthe top of the depolarizing material.

ture.

DR. ALFRED RUGLER.

In testimony whereof, I afiix my signa- 20

